How to use the LDAP Search Filter in Identity Source

The default search filter on Identity Source is, (&(objectClass=User)(objectcategory=person))

For example, if you want to exclude disabled users, you can try this filter

(&(objectCategory=person)(objectClass=user)(!(userAccountControl:1.2.840.113556.1.4.803:=2)))

For more LDAP search filter samples, please take a look of this link,

http://www.morgantechspace.com/2013/05/ldap-search-filter-examples.html